Set the alarm clock for 5:42 am

Leave this tab open — the alarm only rings while the tab stays open.

The alarm goes off in: ::

You can also try the other alarm clocks

Alarm clock for 5:40 am Alarm clock for 5:41 am Alarm clock for 5:43 am Alarm clock for 5:44 am

Going to bed for a 5:42 am alarm

Asleep by 8:27 pm — 6 full sleep cycles, about 9 hours
Asleep by 9:57 pm — 5 full sleep cycles, about 7 hours
Asleep by 11:27 pm — 4 full sleep cycles, about 6 hours

A sleep cycle runs about 90 minutes, and most people take around 15 minutes to drop off. Waking at the end of a cycle feels easier than waking in the middle of one.

5:42 am across the country

London	5:42 am
Birmingham	5:42 am
Manchester	5:42 am
Glasgow	5:42 am
Belfast	5:42 am

Times are worked out live in your browser, so daylight saving is already accounted for.

How to use the online alarm clock

Waiting for 5:42 am gives you a clear point to stop watching the clock and start getting ready for the first train to London. The alarm marks that moment without pulling your attention away every few seconds. With 6:00 am close behind, those 18 minutes can cover the final check for your ticket, keys and anything needed on the journey.

While you wait to leave for the station, the alarm page may sit behind the timetable or another tab you are checking. Moving it into the background does not cancel the setting, but browser sound permissions and your current volume still affect whether you hear it. If you close the alarm page or allow the phone or laptop to sleep, no sound will play, which could leave the first train departing without you. Keeping the page running in an awake browser avoids relying on a signal that cannot be delivered.

A departure this early can make the rest of the morning feel tightly packed, so the useful margin is the time left before your next commitment, not merely the minutes before the train. Allowing a separate buffer after arrival gives you room for a platform change, a short walk or breakfast before the day’s next task. At 5:42 am, that later gap is worth checking before you settle on the alarm.

Common questions

What happens if my laptop goes to sleep before 5:42 am?

The tab sleeps along with it and the alarm will not sound on time, if at all. If you are relying on it, change the power settings so the machine stays awake, or keep a phone alarm running as well.

Do I need an account or an app?

Neither. Choose a time and a sound, press Start, and it runs in this browser tab. Nothing is downloaded, nothing is registered, and closing the page leaves nothing behind on the device.

Can I change the sound?

Yes, there is a short list of tones to pick from before you press Start. Softer sounds are easy to sleep through, so a firmer bell tends to be the safer choice for anything early in the morning.

Will it still be right when the clocks change?

Yes. It reads your device's local clock, so the move between GMT and BST at the end of March and October is picked up automatically, as long as the computer's date, time and time zone are set correctly.